A process for synthesizing TiSi molecular sieve by using complexing agent to improve the stability of Ti source includes such steps as adding the alcohol solution of complexed Ti-contained compound to silicon sol containing ammonium tetrapropylbromide, adding ammonia water or organic amine to regulate pH, reaction to obtain mixture, loading it in a sealed stainless steel crystallizer with teflon liner, crystallizing at 120-200 deg.C for 1-7 days, filtering, washing, drying and calcining.