NOVELTY - A photovoltaic cable has insulating layer (2) comprising ethylene vinyl acetate (EVA), linear low density polyethylene (LLDPE), ethylene methyl acrylate (EMA), maleic anhydride grafted ethylene-vinyl acetate (EVA-g-MAH), magnesium hydroxide, organic montmorillonite, crosslinking sensitizer, lubricant, antioxidant, light stabilizer and copper ion inhibitor; and sheath layer (3) comprising EVA, LLDPE, EMA, EVA-g-MAH, masterbatch (M), magnesium hydroxide, flame retardant, melamine cyanurate, zinc borate, crosslinking sensitizer, lubricant, antioxidant, light stabilizer and copper ion inhibitor.    USE - Photovoltaic cable used in photovoltaic industry (claimed) for power generation.    ADVANTAGE - The photovoltaic cable is environment-friendly; has good mechanical property, flame-retardant property, thermal aging resistance and weather resistance; and can be prepared using simple process with low cost and good processing performance, thus making it suitable for industrial production.    DETAILED DESCRIPTION - A photovoltaic cable comprises an insulating layer and a sheath layer. The insulating layer comprises (pts. wt.) EVA (10-20), LLDPE (40-60), EMA (20-30), EVA-g-MAH (5-10), magnesium hydroxide (50-70), organic montmorillonite (5-20), crosslinking sensitizer (1-2), lubricant (1-3), antioxidant (1-2), light stabilizer (0.2-0.5), and copper ion inhibitor (0.3-0.5). The sheath layer comprises (pts. wt.) EVA (20-40), LLDPE (20-40), EMA (25-45), EVA-g-MAH (5-10), masterbatch (M) (5-10), magnesium hydroxide (40-60), phosphorus-based flame retardant (10-30), melamine cyanurate (15-25), zinc borate (5-10), crosslinking sensitizer (1-2), lubricant (2-3), antioxidant (1-2), light stabilizer (0.5-1), and copper ion inhibitor (0.1-0.3). An INDEPENDENT CLAIM is included for preparation of photovoltaic cable, comprising (A) preparing the insulating layer material pellets; (B) preparing the sheath layer material pellets; and (C) subjecting the insulating layer material pellets and sheath layer material pellets into double-layer co-extrusion process to obtain the insulating layer and sheath layer; covering the insulating layer and sheath layer on the surface of the conductor (1), forming into wire; and cooling, winding, and irradiating the wire to obtain the photovoltaic cable. Step (A) is performed by (a) taking the predetermined amount of EVA, LLDPE, EMA, MAH-g-EVA, lubricant, antioxidant, light stabilizer, and copper ion inhibitor; milling and mixing uniformly; (b) adding with predetermined amount of crosslinking sensitizer, magnesium hydroxide, and organic montmorillonite; milling and mixing uniformly, discharging the mixed material; and (c) extruding the mixed material at 140-170 degrees C, water cooling, drying, and pelletizing to obtain the insulating layer material pellets. Step (B) is performed by (i) taking the predetermined amount of EVA, LLDPE, EMA, MAH-g-EVA, masterbatch (M), lubricant, antioxidant, light stabilizer, and copper ion inhibitor; milling and mixing uniformly; (ii) adding with predetermined amount of crosslinking sensitizer, magnesium hydroxide, phosphorus-based flame retardant, melamine cyanurate, and zinc borate; milling and mixing uniformly, discharging the mixed material; and (iii) extruding the mixed material at 140-170 degrees C, water cooling, drying and pelletizing to obtain the sheath layer material pellets.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic sectional view illustrating the photovoltaic cable.    Conductor (1)    Insulating layer (2)    Sheath layer. (3)