The invention discloses an isolation type Buck-Boost direct current converter, which is obtained by using a Buck type isolation switch unit to replace a Buck unit thereof, or using a Boost type isolation switch unit to replace a Boost unit thereof. The isolation type Buck-Boost converter of the invention retains the same input and output polarities with the double-pipe Buck-Boost converter, low input and output voltage stress, few passive elements and the like; and meanwhile, the converter additionally increases a transformation ratio as compared with the double-pipe Buck-Boost converter, which is more beneficial to optimize design and the control of the converter, so the isolation type Buck-Boost converter of the invention can achieve high efficiency within a wider voltage input range.