Polarization-shift keying (PolSK), which is performed based on two orthogonal polarization states, is investigated in detail by experimental and numerical simulation for data rates of 10 and 40 Gb/s. Using a general Mach-Zehnder intensity modulator, a new type of PolSK transmitter is presented and demonstrated by polarization coupling technology. And then the PolSK transmission is experimentally demonstrated in a 50-km single mode fiber system, whose eye diagrams show that the PolSK transmitter works well at 10 Gb/s and the power fluctuation is ~8%. Further simulation reveals that the PolSK has great potential in long distance transmission with data rate of 40 Gb/s, while its error-free distance goes beyond 2 100 km.