The Ricci flow equation on n dimensional complete noncompact Khler manifolds is studied by solving the PoincaréLelong equation,if the following condition is satisfied:∫r0skt(x,s)ds≤qC log(2+r),then a necessary and sufficient condition for the existence of the immortal solution to the Ricci flow at any meric t time is obtained.It extends the result of Reference[1]that they get a necessary and sufficient condition for the existence of the immortal solution to the Ricci flow at metric t=0 time.