A bicycle trainer compensation algorithm based on multi-groove belts sliding relative to one another includes: determining a load interval and a rotating speed range, recording an external driving torque, a rotating speed, a measured torque and a no-load mechanical loss of the bicycle trainer under conditions of different loads and different rotating speeds, and obtaining a relationship between a mechanical loss of a whole machine and the different rotating speeds, the different loads, and the no-load mechanical loss, fitting a plurality of sets of relationships to obtain an algorithm relation, verifying universality of the algorithm relation, and further fitting to obtain a compensation algorithm relation, and verifying whether a compensation accuracy of the compensation algorithm relation is satisfied within an error requirement.