In order to illustrate the role of alkali treatment of bamboo particles reinforced polyvinylchloride composites (BPPC), bamboo particles were treated by alkali aqueous solution with a serial concentration of 0.5%, 1%, 2%, 5% and 10%. Mechanical, thermal properties of alkali treated BPPC and micro-micrographs of the fracture surface were researched and compared with raw bamboo particles fabricated BPPC respectively. Results showed that tensile strength of BPPC increased before the solution reached the concentration of 5% and got a maximum value of 15.07MPa at the concentration of 5%. The curve decreased significantly as the concentration of solution went higher as to 10%. Modules of rupture got a highest value of 44.73MPa till reached the concentration of 2% and then decreased. Modules of elasticity increased in the whole before reached the concentration of 5% and the maximum value was 4362.48MPa which was 5 times more than the original bamboo particles. DSC curves illustrated that raw bamboo particles mixed with PVC showed a higher Tg which meant that raw fiber was not well compatible with PVC and BPPC treated with alkali solution performed a better compatibility. According to SEM observations, interface interaction of fiber-matrix that were modified of alkali solution upon bamboo particles appeared a better interlock action correlated to higher mechanical properties and better compatibility between fiber and matrix. Hence, the use of alkali treated bamboo particles as reinforcement was a feasible and competitive method of creating new materials.