Provided are an apparatus and method for implementing an IPSec engine in IXDP2851. The apparatus for implementing an IPSec engine in IXDP2851 which is an IXP2850 network processor development platform, includes: a packet classifier/forwarding microblock classifying packets into an inbound packet and an outbound packet, using received packet information; determining whether IPSec processing should be performed on the inbound packet and the outbound packet, and performing packet forwarding on a packet not requiring the IPSec processing; an outbound IPSec processing microblock; an inbound IPSec processing microblock; and an IPSec forwarding microblock receiving packet information of a packet subjected to IPSec processing and performing forwarding on the corresponding packet. Therefore, by separately processing packets requiring IPSec processing and packets not requiring IPSec processing, it is possible to implement an IPSec engine without influencing a processing speed of general packets not requiring IPSec processing.