In this paper, a method that combines radio frequency (RF) plasma with hot filament (HF) chemical vapor deposition (CVD) together has been used to prepare 3C-SiC film. The samples obtained through the above method have been systematically demonstrated by atom force microscopy (AFM), x-ray diffraction (XRD). Its concentration is measured to be p=1.33×1017cm -3 using Hall effect. The samples have been divided into two parts: ones ohmic contact is made with deposition of aluminum directly on its surface. Alternately, the other's metal contact is deposited following a polysilicon pre-deposition. Both of them are annealed at 450, 600 and 710°C, separately. The specific contact resistance of sample without polysilicon annealed at 710°C is ρc = 0.014 Ω cm2 and that of sample with polysilicon annealed at the same condition exhibits an improved property. Its specific contact resistance can be lowered to be ρc=3. 5×10-4 Ω cm2. The mechanism for this experimental result has been explained in this paper, too. And attempt to add nanometer grain on polysilicon to lower barrier.