f[x_,y_]:=0.2 x+0.1y

G=ParametricPlot3D[{x,y,f[x,y]},{x,-1,4},{y,-1,4},BoxRatios->{5, 5, 3},Mesh->None,Boxed->False,Axes->False,PlotStyle->Opacity[0.2]]

K=Graphics3D[Style[{Text["K",{4.1,4.1,f[4,4]-0.2}]},Large]]

Py=ParametricPlot3D[{0,y,z},{y,-1,4},{z,-1,3},MeshFunctions->{#3&},Mesh->3,PlotStyle->Opacity[0.2]]

Px=ParametricPlot3D[{x,0,z},{x,-1,4},{z,-1,3},MeshFunctions->{#3&},Mesh->3,PlotStyle->Opacity[0.2]]

Yb=Graphics3D[Style[{Text["平面 y=b",{4.1,0,-0.2}]},Large]]

Lx=ParametricPlot3D[{x,0,0.2x},{x,-1,4}]

Ly=ParametricPlot3D[{0,y,0.1y},{y,-1,4}]

Lz=ParametricPlot3D[{0,0,z},{z,-1,3}]

Fr=Graphics3D[Line[{{-1,-1,f[-1,-1]},{4,-1,f[4,-1]},{4,4,f[4,4]},{-1,4,f[-1,4]},{-1,-1,f[-1,-1]}}]]

Pt=Graphics3D[Style[{{Red,Ball[{0,0,0},0.1]},{Red,Ball[{4,0,f[4,0]},0.1]},Text["A",{0,0.1,0.3}],Text["P",{4.2,0.1,f[4,0]+0.2}]},Large]]

Show[G,K(*,Yb*),Fr,Px,Py,Lx,Ly,Lz,Pt]