A　method　to　quantitatively　evaluate　the　TEM　(transmission　electron　microscopy)　image　quality　is　proposed　by　calculating　the　point　spread　function　equivalent　area　(the　area　of　independent　variable　region　whose　normalized　point　spread　function　value　is　not　less　than　0.7071).　The　tilt　series　of　practical　ultra-high-voltage　TEM　images　for　three-dimensional　reconstruction　is　analyzed　and　the　quantitative　relationship　between　TEM　image　quality　and　specimen　tilt　angle　is　acquired.　Followed　the　single-axis　tilting　projection　collection,　the　image　quality　is　worsened　with　the　increase　of　the　specimen　tilt　angle　and　especially　for　the　tilt　angle　larger　that　60°　the　quality　declines　acutely.　The　point　spread　function　equivalent　area　at　30°,　60°　and　70°　is　2.5,　4.5　and　11.7　times　as　wider　as　that　at　0°,　respectively.　This　effect　restricts　to　improve　the　three-dimensional　reconstruction　resolution　by　increasing　the　specimen　tilt　range　and　suggests　an　optimum　tilt　range　for　the　specimen　in　the　three-dimensional　reconstruction　form　TEM　images.