The invention discloses an expandable polystyrene product and a production method thereof. The expandable polystyrene product is made by processing the following ingredients in parts by weight: 100 parts of styrene, 110 to 150 parts of water, 0.25 to 0.5 part of evocating agent A: BPO, 0.04 to 0.1 part of evocating agent B: CP-02, 7 to 10 parts of vesicant: pentane, 0.05 to 0.15 part of dispersant: TCP, 0.05 to 0.2 part of suspending agent: polyethylene wax and 0 to 0.01 part of emulsifier: GMS, and the ingredients react and are evocated as per certain sequence at rated temperature by stages. Compared with the prior art, the product has uniform particle size distribution, high foaming multiplying factor (no less than 90), favorable elasticity, stable quality, high yield rate and favorable comprehensive economic and technical norms, and the production method of the product has little pollution on environment.