The invention discloses a pair of roller skates. Each roller skate comprises a frame, at least two rollers arranged on the frame and a braking system, wherein the frame comprises a bracket and penetration parts; the bracket contains the rollers and the penetration parts are distributed on the bracket and are used for containing the foot or shoe of a user. The roller skates are characterized in that the braking system comprises a driving device controlled by bending and extending movement of a knee joint and a brake driven to work by the driving device; the brake comprises a braking part; the driving device comprises a first member, a second member and a control line; the first member is hinged to the second member; when the knee joint of the user carries out bending and extending movement,the first member can rotate relative to the second member, and the control line is connected with at least one of the first member and the second member. The roller skates disclosed by the inventioncan realize braking in a convenient-fast-reliable manner.