An athermal low polarization-independent 49-channel arrayed-waveguide grating (AWG) multiplexer relying on a ultraviolet (UV) curable all-polymer approach is designed and fabricated by simple direct ultraviolet photolithography process. The transmission properties of the AWG around the central wavelength of 1550.918 nm with the wavelength spacing of 0.8 nm are optimized by Matlab programming. By properly adjusting the positive coefficient of thermal expansion of the polymer substrate and the negative thermo-optic coefficient of the polymer waveguide, athermal and low polarization-independent characteristics of AWG device are realized. The actual fiberfiber insertion loss at each channel is from 5.51 dB to 10.62 dB, and the crosstalk of the 49 channels is larger than 20 dB. Both polarization drifts and temperature shifts of the AWG are 0.08 nm and 0.03 nm/K, respectively. The new technique can be well suited for realizing optical integrated circuits with excellent performances.