Based　on　the　total　focus　method　(TFM)　of　imaging　technology,the　imaging　examination　and　quantitative　characterization　of　surface　opening　cracks　on　wind　turbine　main　shaft　were　carried　out.　An　array　detection　simulation　model　of　wind　turbine　main　shaft　containing　surfacebreaking　cracks　was　established,and　the　TFM　imaging　detection　was　carried　out　using　the　simulation　data　and　the　total　focus　algorithm.Based　on　the　solid　directivity　function　of　planar　circular　piston　acoustic　source,a　compounding　total　focus　imaging　algorithm　with　bi-directional　compensation　and　weighted　by　sign　coherence　factor　was　proposed,　and　the　algorithm　was　verified　using　the　simulation　data.　The　results　showed　that　the　improved　algorithm　could　effectively　eliminate　the　artifacts　and　improve　the　imaging　quality.Cracks　on　the　shaft　specimen　were　imaged　and　quantified.Moreover,the　axial　positioning　error　of　the　cracks　is　less　than　2%,　and　the　depth　quantization　error　is　less　than　8%.　©　2024　Editorial　Board　of　Journal　of　Basic　Science　and.　All　rights　reserved.