We report our recent results from multiwavelengths studies of microquasars, focusing on X-ray data of GX 339-4 and GRS 1915+105 obtained with Suzaku and other observatories. The broad band coverage and high energy resolution achieved with Suzaku (or a combination of Chandra/HETGS and RXTE) enable us to perform the most reliable spectral analysis both on iron-K features and continuum, and thus to best constrain the accretion disk structure of microquasars and its relation to the jet formation at various mass accretion rates.