The invention relates to a method for preparing a thick nickel coating on the surface of a semiconductor material. The method is characterized by comprising the following steps of degreasing an N-type or P-type Bi2Te3 material for removing oil; blowing sand with No. 46 zirconium corundum under the conditions of a sand-blowing pressure of 0.1-0.2MPa, a blowing distance of 150-200mm and an angle of 45-80 degrees; and spraying industrially pure nickel powder of which the purity is equal to or greater than 99% and the grain size is -45+15mu m by virtue of a plasma spray gun of which the current is 500-700A, hydrogen is 5-7L/min and argon is 40-60L/min under the conditions of a power feeding rate of 80-120g/min, a spraying distance of 150-180mm, a gun speed of 800-2000mm/s and the deposit thickness of 10-20mu m for each time to obtain the nickel coating of which the total thickness is 20-80mu m. By the method disclosed by the invention, the thick nickel coating having the thickness greater than 20mu m can be obtained on the surface of the semiconductor material, the method has the advantages of high coating deposition efficiency, high deposition speed, uniform thickness, no high requirement on the spray raw material and excellent bonding force between the coating and the semiconductor material.