Nylon- 1010 samples were treated by two methods,method I: annealing after melting；method II：annealing after quenching of melt at room temperature．The diffractional patterns of the isothermal crystallization samples were deter-mined by WAXD．There are three distinct peaks at 20=8.5°，20.05°and 23.92°respectively，the amorphous samples have only a broad peak at about 20=21.50°．Based on the graphic multipeak resolution method，the degree of crystallinity (Wc.x) of the samples after various heat treatments were calculated．In order to confirm the results，the degree of crystallinity( Wc.d) from density measurement and the degree of crystallinity (Wc.h) from DSC measurement were also shown．The Wc,a (a=x，d，h) of every sample has maximum value of the normal distribution with temperature change，indicating that both method I and nethod II have the most suitable annealing temperature (Th) for crystallization of the sam-pies．The Wc,x of the samples from method I were higher than those of the sam-ples from method II when the Th were the same，indicating that method I is bet-ter than method II for the crystallization of Nylon-1010．Based on Variance-Range Function method，the single peak of 002 was sepa-rated into crystalline and amorphous partions by using a computer．After all pro-files were corrected for back：ground，Lorentz factor，polarization factor and absorption factor，the variance W2θ=W0+Kσ can be obtained．The plot of variance (W) vs range (σ) is a straight line．The values of the slope k and intercept Wo were obtained．The crystallite size Lhkl and paracrystallinity parameter g can be calculated．The Lhkl in terms of the Scherrer Equation were also calculated．The result in-dicated that Lhkl calculated from the two methods have maximum values when plotted against the temperature change．The Lhkl of the samples from method I are higher than those of the samples from method II when the Th are the same．The values of g are on the reverse，indicating that the crystal lattices of the samples from method I are more perfect．These showed further method I is advantageous for the formation and stability of the crystals．