NOVELTY - Co-producing water-soluble nitrogen, phosphorus and potassium (NPK) complex and feed calcium phosphate salt using defluorinated phosphate comprises (a) subjecting defluorinated phosphate to primary neutralization reaction, and carrying out solid-liquid separation; (b) subjecting resulting filtrate A to secondary neutralization reaction; (c) subjecting the filtrate B to tertiary neutralization, and carrying out solid-liquid separation to obtain filter cake C and filtrate C; (d) preparing water-soluble NPK fertilizer using the filtrate C; and (e) obtaining feed-grade calcium phosphate salt.    USE - The method is useful for co-producing water-soluble NPK complex and feed calcium phosphate salt using defluorinated phosphate (claimed).    ADVANTAGE - The method: has high utilization raw material rate; produces fertilizer with high purity; does not discharge waste; is environmentally friendly; and produces high value-added products.    DETAILED DESCRIPTION - Co-producing water-soluble nitrogen, phosphorus and potassium (NPK) complex and feed calcium phosphate salt using defluorinated phosphate comprises (a) subjecting defluorinated phosphate to primary neutralization reaction with a primary neutralizer to obtain solid-liquid mixture, carrying out solid-liquid separation to obtain filter cake A and filtrate A, where the mol ratio of defluorinated phosphate and primary neutralizer is 1-3.5:1, and the primary neutralizer is calcium oxide, calcium carbonate, calcium hydroxide or tricalcium phosphate; (b) subjecting the filtrate A to secondary neutralization reaction with a secondary neutralizer to obtain a solution with pH of 2.5-4, carrying out solid-liquid separation to obtain filter cake B and filtrate B, where the secondary neutralizer is liquid ammonia, aqueous ammonia, ammonium carbonate, ammonium bicarbonate, diammonium phosphate or triammonium phosphate; (c) subjecting the filtrate B to tertiary neutralization reaction with a tertiary neutralizer to obtain a solution with pH of 4-8, carrying out solid-liquid separation to obtain filter cake C and filtrate C, where filtrate C is nitrogen, phosphorus and potassium (NPK) complex fertilizer solution, and the tertiary neutralizer is potassium hydroxide, potassium carbonate, potassium bicarbonate, dipotassium hydrogen phosphate or tripotassium phosphate; (d) preparing water-soluble NPK fertilizer using the filtrate C; and (e) mixing the filter cake A, filter cake B and filter cake C, and drying, or drying the filter cakes A, B and C, and then mixing to obtain feed-grade calcium phosphate salt.