The architecture optimization of a three degrees of freedom (3-DOF) planar cable-driven parallel manipulator (CDPM) with multiple objectives has been implemented by means of GA approach in this paper. Firstly, the kinematics and statics issues of the CDPM are addressed, which allows the generation of the feasible workspace restricted by both the cable length limits and tension bounds. Then, the optimal designs with respect to the feasible workspace with separated considerations of dexterity and stiffness performances are carried out to obtain the architectural parameters of the manipulator. The simulation results illustrate that the separated optimizations result in reverse variation tendencies of the design parameters. In order to deal with such problem, the multi-objective optimal design for a mixed performance index is accomplished afterwards. The optimization results demonstrate the compromise effects of the proposed multi-objective function, and the results are valuable in designing a planar 3-DOF CDPM.