The relationship between properties of BF-WPC and the content of BF were studied, when wood-plastics composite (WPC) was reinforced by 12 mm and 3 mm short basalt fiber (SBF). The results showed that there may have some uneven distributions of SBF in WPC, when the content of 12 mm BF exceeded 30%. Restricted to the uneven distribution and the quantity of “end weak’’, it formed the close comprehensive property of BF-WPC by the length of 12mm and 3mm BF. The comprehensive property of BF-WPC has a maximum range of 15%-30% of the content of 12 mm BF. Compared to pure WPC, the tensile and bending strength of BF-WPC have improved. However, the reinforce effect of BF-WPC is different and is dependent on the index of each property. The BF-WPC plate can be developed with different properties and be a cost-effective material by choosing different length and content of BF.