A compact arrayed waveguide grating (AWG) triplexer based on SU-8 strip waveguides is designed and realized. The cross-order design method utilizing the spectral periodicity of AWG don′t need to change the layout of AWG, and there is no need of extra component to cover all three operating wavelengths of 1310 nm, 1490 nm and 1550 nm for the triplexer. The core layer is SU-8 polymer, the under-cladding is SiO2, and the upper-cladding is air. The AWG triplexer can be easily fabricated by using direct ultraviolet photolithography process without additional etching process. The simulation results show that the 3 dB bandwidth of three working channels are all larger than 11 nm, and the polarization dependence wavelength shift is less than 0.65 nm. Experimental results verify the cross-order design. For transverse magnetic (TM) polarization, the excess loss of the second and the third wavelength channel is about 3 dB, which is about 7 dB for the first. The crosstalk is better than -15 dB. The whole device has a compact size of as small as 1.3 mm×0.402 mm.