Abstract: We present particular and unique solutions of singlet and non-singlet Dokshitzer-Gribov-Lipatov- Altarelli-Parisi (DGLAP) evolution equations in next-to-next-to-leading order (NNLO) at low-x. We obtain t-evolutions of deuteron, proton, neutron and difference and ratio of proton and neutron structure functions at low-x from DGLAP evolution equations. The results of t-evolutions are compared with HERA and NMC lox-x and low-Q2 data. We also compare our result of t-evolution of proton structure function with a recent global parameterization. PACS No.: 12.38.Bx, 12.39-x, 13.60Hb.