A water supply simulation method for interlaced system of river and canal system based on groundwater model, includes: S1. constructing simulated water conveyance channel based on first data, and performing attribute definition on water conveyance channels; S2. acquiring initial seepage, evaporation and discharge; S3. performing reverse water demand calculation; S4. performing sequential water supply simulation; S5. acquiring corresponding water head, obtaining current seepage, evaporation, discharge, head-end water demand and water consumption demand of each water conveyance channel based on water head; S6. judging whether current iteration is converged according to water head, if yes, proceeding to S7, otherwise returning to S3 after update; S7. judging whether there is next time period, if yes, returning to S3 after update, otherwise proceeding to S8; and S8. judging whether there is a next stress period, if yes, returning to S3 after update, otherwise outputting the result obtained in S5, and ending.