TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: In (a), the organic solid waste material is added into the first acidified reactor at the zero day; and the organic solid waste material is added into the second acidified reactor at the m day; by parity of reasoning, when at the (n-1)x m day, the organic solid waste material is added into the n acidified reactor; the rest solid is taken out of the first acidified reactor at the nasteriskm day and part of the liquid part is kept in the reactor and the organic solid waste material with the same amount with the solid which is taken out is added into the reactor; the rest solid is taken out after the second reactor reacts for n x m days; part liquid is kept in the reactor and the organic solid waste material with the same amount with the solid which is taken out is added into the reactor; by parity of reasoning, the rest solid is taken out after the n reactor reacts for nasteriskm days; part liquid is kept in the reactor and the organic solid waste material with the same amount with the solid which is taken out is added into the reactor; and n is more than or equal to 2 and m is more than or equal to 1. Step (c) takes the way of batching material; percolate whose pH value is adjusted by (b) is pumped into the methanation reactor which is filled with the inoculated material; the material is added for p times everyday and the amount of the material which is added every time is 1/p of the gross of collected percolate in the percolate collecting box. In (c), the inoculated material is the anaerobic activated mud in the sewage disposal plant. The methanation reactor is the continuous stirred tank reactor (CSTR), plug flow reactor (PFR), bended flow reactor (BFF), upper-flow anaerobic sludge bed reactor (UASB), anaerobic biological rotary table reactor (ABR), sequencing batch activated sludge reactor (SBR), anaerobic biological filtering tank (ABF), upper-flow anaerobic filtering tank (UAF) or expanded grain sludge bed (EGSB) anaerobic reactor.