Protein kinases regulate the signal transduction pathways in cell by phosphorylating the protein kinase substrate, and they are important targets in drug design. Protein kinase A (PKA) is the first kinase that was obtained X-ray structure of its catalytic domain, and is regarded as prototype for protein kinase superfamily. The progress in computational chemistry study of protein kinase A has been reviewed, including the molecular dynamics simulation study of PKA holoenzyme and its C subunit and R subunit in aqueous solution, phosphoryl transfer mechanism, the binding free energy predicting and flexible docking of C subunit with its inhibitor balanol. Various computational approaches are applied to this system, including molecular dynamics simulation, dock, homology modeling, QM/MM.