A SIMPLE type algorithm,which is called SIMPLE-P,is presented here.The new algorithm lays emphasis on pressure boundary conditions which are ignored by SIMPLE.The SIMPLE-P algorithm has a great advantage over SIMPLE algorithm when the boundary pressure,instead of velocity,is given.It is pointed out that to obtain the full treatment of pressure boundary conditions,the effects ofboundary inner control volume must be taken into account.The examples given here prove that the SIMPLE-P algorithm is quite effective.