In corner-pumped configuration, dichroic mirror of high transparency for pump light and high reflection for laser light can be avoided, and with laser crystal of low doping concentration the pump absorption efficiency is still acceptable, so this pump configuration is suitable for demanding pumping requirements of radiation-balanced laser (RBL). The formula for the laser crystal width is optimized in corner-pumped configuration to avoid the leakage of the pump light from the crystal pumping corner. When the pumping wavelength is 992.8 nm and the laser crystal of RBL is Yb:KGW with 5% doping concentration, ray trace method is applied to simulate corner-pumped configurations both with and without diffusion technique numerically. According to efficiency and uniformity of pumping light absorption, in the design of both configurations the best pump incident angle is 45° and the best pump total reflection number is 1, but the corner-pumped configuration with diffusion technique is about 20% more efficient than the that without it.