This　study　made　an　attempt　to　understand　and　control　the　heteroepitaxial　growth　of　GaN　from　the　view　of　the　essential　behaviors　of　crystal　growth.　Through　a　comparison　of　the　nonpolar,　polar　and　semipolar　GaN　epitaxial　film,　the　influence　of　lateral　growth　on　the　surface　pit　formation　mechanism　has　been　investigated.　For　a-plane　GaN,　the　lateral　growth　velocities　of　the　less　inclined　{20-21}　and　{11-22}　facets　are　approaching　to　the　velocity　of　{10-11}　facet　under　high　temperature,　so　that　the　surface　pit　was　transformed　from　a　triangular　shape　to　a　pentagonal　one.　For　c-plane　GaN,　the　size　of　the　surface　pit　produced　by　screw　dislocation　is　determined　by　the　lateral　growth　of　the　pit　facets.　A　slow　lateral　growth　rate　of　the　inclined　facets　{10-11}　compared　with　the　vertical　growth　rate　of　(0001)　facet　under　low　VIII　ratio　would　enlarge　the　pit　size.　For　(11-22)　semipolar　GaN,　surface　pit　is　rarely　observed,　because　the　vertical　growth　velocity　of　{11-22}　plane　is　slow　compared　with　the　lateral　growth　rate　of　the　inclined　facets,　such　as　{11-20}　and　(0001).