This paper presents a compact double-sided cooling Gallium Nitride (GaN) power module with low parasitic parameters. The GaN bare dies are sandwiched between two ceramic substrates with high thermal conductivity to achieve efficient double-sided cooling capability. Through careful design and layout optimization, the bus decoupling capacitors and core drive components are successfully integrated into the module to reduce critical parasitic parameters. The thermal and parasitic characteristics of the module are analyzed and optimized. Finally, a double-pulse-test platform is built based on the presented 650V/30A GaN power module. The results show that the power loop inductance is reduced to 0.95 nH and the gate loop inductance is reduced to about 2nH. The dv/dt of the drain-source voltage can be as high as 150V/ns, while the overshoot is only 10%.