The invention provides a synthesis method for Ti3SiC2 powder. The synthesis method comprises the following steps of S1: mixing materials: evenly mixing raw materials and mixed fused salt at a ratio toobtain mixed powder, wherein the raw materials are the mixture of Ti powder, Si powder and C powder, and the mixed fused salt is the mixture of KCl powder and NaF powder; S2: calcining: calcining themixed powder obtained in the S1 to obtain a calcined material; S3: washing: washing the calcined material obtained in S2 to obtain a washed material; S4: drying: drying the washed material obtained in S3 to obtain Ti3SiC2 powder. The synthesis method has the effects that synthesis steps are greatly simplified, a production process is shortened, cost is lowered, technological parameters can be easily controlled, industrialization can be easily realized, the shape and the size of a powder product grain can be effectively controlled, and the dispersibility and the purity of the powder are improved.