The utility model discloses a continuously adjustable DC power supply, including transformer T, rectifier bridge Q, resistance R1, electric capacity C1, triode VT1, potentiometre RP1 and one -way silicon controlled rectifier VS, transformer T coil L1 connects at both ends 220V alternating current both ends respectively, and transformer T coil L2 connects at both ends rectifier bridge Q pin 1 respectively and connects electric capacity C1, resistance R1, triode VT1 collecting electrode and triode VT2 collecting electrode respectively with 4, rectifier bridge Q of rectifier bridge Q pin 2. The utility model discloses continuously adjustable DC power supply's DC voltage is from 3V to 15V continuously adjustable, and maximum current can reach 10A, has the temperature compensating characteristic, uses the standard voltage source integrated circuit TL431 of high accuracy, makes the precision of voltage regulation higher, and circuit structure is simple, and is small, especially adapted using widely.