The invention relates to chemical plating on the surface of a metal material, in particular to a low-temperature ultrasonic wave assisted chemical Ni-Cu-P plating solution used for the surface of a low-carbon steel base material as well as a chemical Ni-Cu-P plating method. The characteristics include adopting nickel sulfate and copper sulfate as the main salt of the plating solution, sodium hypophosphite as a reducing agent, sodium acetate as a buffer, trisodium citrate and lactic acid as complexing agents, succinic acid and glycine as well as ammonium hydrogen fluoride as combined accelerators, potassium iodide and thiourea as stabilizers to prepare the chemical Ni-Cu-P plating solution, and applying the chemical Ni-Cu-P plating solution on the surface of a low-carbon steel substrate bylow-temperature ultrasonic wave chemical plating. In the invention, the formula of the plating solution is environment-friendly, meets the environment-friendly requirement of clean production and reduces pollution to environment. The method for chemically plating Ni-Cu-P on the surface of the low-carbon steel substrate obviously lowers the plating application temperature, enables the deposition speed to be fast and effectively improves the performance of the low-carbon steel substrate.