The invention discloses a segmented linear compensated CMOS band gap reference voltage source, characterized in that it comprises IPTAT current generation part, ICTAT current generation part, low temperature segment compensation current ICL generation part and high temperature segment compensation current ICH generation part. On the basis of traditional first-order curvature compensation, it divides the whole temperature range into high, medium and low temperature segments, compensates output voltage in each temperature range respectively and makes the output voltage have multiple local extremum points in the whole temperature range to achieve the segmented compensation purpose, so as to effectively improve the temperature characteristics of output voltage reference, reduce temperature coefficients and improve accuracy of output voltage. Besides, it can change amplitude of output voltage by regulating resistor ratio value, relatively flexible to use. The whole circuit has low power consumption and occupies smaller chip area.