The diamond particles and films were deposited on Si and qurtz substrate for $CH_4-H_2$ mixed gas by using RF plasma CVD. The temperature of substrate and the thinkness of films deposited on Si substrate were uniformly kept up by inserting metal plate between substrate and substrate holder. On increasing the reaction pressure in the same discharge power, the morphologies of films were changed from well-defind films to micro-crystal or ball-like. When diamond films were deposited on Si substrate from $CH_4-H_2$ mixed gas, we obtained well-defined diamond films at lower concentration than 0.5 vol% of $CH_4/H_2$. The deposited diamond films were indentified by SEM, XRD and Raman spectroscopy.