Based on the structure of composite right/left-handed transmission line (CRLH-TL), a novel phase shifter with higher power capacity is proposed. What's more important, a new accurate equivalent circuit of the CRLH-TL element is proposed and its validity can be proved by the accordance of the theoretical and simulated results. In the present structure, switches of phase shifters are mounted on fingers of CRLH-TLs, thus the power through a single switch is only a fraction of that through the whole phase shifter. As a result, the power capacity of the present phase shifter can be greatly improved. Besides, the present phase shifter possesses other advantages such as low cost, small size and easy fabrication. Phase shifts can be achieved by changing the state of the switches. Then, a 4-bit phase shifter and is designed as examples. Finally we test the power capacity of the phase shifter, and its power capacity is higher than most of the traditional ones.