Electrical discharge machining (EDM) is an excellent technology to machining die and mold, but it is uneasy to obtain mirror-like surface. Powder-Mixed dielectric electrical discharge machining (PMD-EDM) is the innovative technology of EDM process, which can improve the quality of machined surface and applied in EDM finish machining now. The powder is usually hard particles, such as Al, Cu, Cr and Si in PMD-EDM. This paper presents a new research of PMD-EDM with suspending soft particles and abrasive grits in the dielectric fluid, especially focus on surface roughness. Experimental result shows the EDM process with polymer particles and abrasive grits can be carried out in silicone oil and the surface roughness has the finer improvement when increasing the rotation speed. Also, the effect of hard particles suspending in dielectric fluid are also discussed and compared. The surface roughness using polymer particles and abrasive in specific condition was better than only hard particles in silicone oil. Moreover, mixing abrasive and polymer in EDM can perform the polishing process.