PURPOSE: To obtain a production process whereby a polysilicon-polyamide block copolymer having a high degree of polymn. and excellent mechanical strengths is obtd. in a high yield without causing problems with safety and hygiene by using a specific solvent.

CONSTITUTION: This process for producing a polysiloxane-polyamide block copolymer represented by formula I (wherein L is a 1-6C alkylene; R1 and R2 are each an optionally fluorinated a 1-6C alkyl, aryl, or aralkyl group; Ar1 and Ar2 are each an arom. group; n is 10-200; m is 1-100; and p is 2-200) contains the step of reacting a polysiloxane represented by formula II with a polyamide represented by formula II in the presence of an org. base in a glycol diether solvent represented by formula IV (wherein R3 is a 2-4C alkylene; R4 and R5 are each a each a 1-4C alkyl; and t≥1). A polyethylene glycol dialkyl ether is esp. pref. as the solvent.