A SOI-based 25-channel AWG with 200 GHz channel spacing is demonstrated. The minimum distance between the input waveguides (Δxi)/ output waveguides (Δxo)/ arrayed waveguides (d) is optimized respectively. Then the boundary structures between the free propagation regions (FPRs) and the arrayed waveguides (W2/L2/L3) are optimized in detail. The experiment results show that the insertion loss of the AWG is 5~7 dB, and the crosstalk of it is 13~15 dB. Compared with our previous work, the performance of AWG in this paper has been improved greatly, and further methods to improve the performances of insertion loss and crosstalk have been proposed as well.