The invention discloses a device and a method for detecting blood pressure and oxyhemoglobin saturation simultaneously, and belongs to the technical field of radial artery detection. By the device and the method, the problems that the blood pressure and the oxyhemoglobin saturation are needed to be detected by using separate sensors at present, so more electronic components of a detection device are needed, and the detection device is complex in structure are solved. The device comprises a cuff, a pulse generator, a photoelectric plethysm sensor, a wave crest retainer, a first high-pass filter, a first low-pass filter, a second high-pass filter, a second low-pass filter, an analog to digital (A / D) converter, a digital to analog (D / A) converter, a computer, an electro-pneumatic converter, an air pump, a power amplifier, and a pressure sensor; and according to the method, the radial artery is used as a detected target, the blood pressure, and the oxyhemoglobin saturation of arterial and venous blood can be detected simultaneously, and the oxyhemoglobin saturation of the venous blood is measured indirectly. The device and the method are suitable for detecting the blood pressure and the oxyhemoglobin saturation simultaneously.