Dual　wavelength　digital　holography　is　an　effective　technique　for　the　measurement　of　object　profile　with　the　discontinuities　especially　for　an　object　of　thickness　greater　than　single　wavelength.　However;　phase　information　of　the　two　reconstructed　images　obtained　by　two　different　wavelengths　usually　can＇t　match　precisely.　As　a　result,　signal　to　noise　ratio　(SNR)　of　reconstructed　image　of　the　equivalent　wavelength　increases　and　the　real　phase　information　of　object　can＇t　be　measured　accurately.　It　is　because　in　space　multiplex　system,　the　focal　plane　asymmetry　is　produced　due　to　the　discrepancy　between　the　two　wavelengths　through　the　splitter　and　CCD　front　lens,　which　worsens　the　mismatching　of　the　two　phase　information.　In　this　paper,　the　method　of　refocusing　two　holograms　with　autofocusing　algorithm　based　on　the　gradient　square　criterion　is　proposed.　The　matching　error　can　be　decreased　easily　since　two　real　distances　for　the　reconstruction　of　object　information　are　obtained.　Considering　the　advantages　of　autofocusing　algorithm,　the　phase　of　sample　can　be　measured　quickly　with　accuracy.　This　method　provides　a　basis　for　real-time　reconstruction　of　dual　wavelength　digital　holography　in　micro-structure　measurement　field.　Finally,　the　off-axis　Fresnel　digital　holography　is　implemented　with　Mach-Zehnder　setup　to　verify　the　effectiveness　of　the　proposed　method　and　the　three-dimensional　morphology　of　phase　grating　is　measured　successfully.