The utility model relates to a high accuracy absolute value circuit, provide one kind with low costs, anti -interference, can be accurate the high accuracy absolute value circuit of sinusoidal wave absolute value of output sampled value. Including difference sampling circuit, decoupling circuit and the absolute value rectifier circuit who establishes ties in proper order, this circuit adopts the combination of operational amplifier, resistance and diode to constitute the absolute value circuit, and this circuit connection is simple, and there is forward voltage drop in it to have solved use rectifier diode on the one hand, can not get the problem of the absolute value voltage of high accuracy, also need not to use simultaneously dedicated chip, practices thrift the cost, on the other hand through with the using coordinately of difference sampling circuit and decoupling circuit, not only improved the precision of circuit, filtering simultaneously the interference.