A packet cipher algorithm based encryption processing device includes a key expand unit and an encryption unit. The key expand unit comprises a key expand unit data registration component and at least one key expand unit data conversion component. The encryption unit comprises an encryption unit data registration component and at least one encryption unit data conversion component, and the number of the encryption unit data conversion component is the same as that of the key expand unit data conversion component, and besides, they are one to one. A sub-key output of each key expand unit data conversion component connects the corresponding sub-key input of each encryption unit data conversion component to solve the technical problems that the encryption efficiency of the prior packet cipher algorithm based encryption processing device is low and the cost is high. The advantage of the present invention is reducing the resource consumption and further reducing the achievement cost of the device under the premise of keeping the high efficiency of the prior art.