The utility model provides a bicycle transmission mechanism relates to transmission mechanism technical field, and this bicycle transmission mechanism includes mounting bracket, pivot, main
sprocket disc, from
sprocket disc, chain, recess, fixed
bevel gear disc, main conical gear disc, from conical gear disc, pedal rod, pedal, and the pedal rod is connected through the screw rod, nut with main conical gear disc, one side of main conical gear disc is provided with the movable
bevel gear disc that is engaged with fixed
bevel gear disc, one side of movable bevel gear disc is provided with a plurality of fixed rods that are penetrated and are slidably connected with main conical gear disc, one end of fixed rod is provided with the
fender, spring is set up on fixed rod, and spring is located between main conical gear disc and movable bevel gear disc, because this bicycle only has a set of transmission mechanism, so the length of bicycle is basically same with the length of conventional single person's bicycle, improves the flexibility of bicycle riding, also satisfies the demand of double people's bicycle riding, can also reduce the influence to surrounding riders.