In this work, a spiro diborate (SDB), different from the traditional polymers, was synthesized from glycerol monolaurate and boric acid, and was evaluated as viscosity-reducer and pour point depressor for crude oil. The evaluation showed that this spiro compound can improve the flow properties of crude oil samples by reducing the viscosity of crude oil by 82.3% at most and depressing the pour point by 8.0 degrees C. The role of SDB in limiting the degree of cocrystallization can be further confirmed by the average particle size and the particle morphology analysis of saturated hydrocarbons (HC) component illustrated from microscopic crystal morphology. So it can be concluded that the high content of saturated HC makes for the effective viscosity reduction.