By mixing natural rubber latex uniformly with methyl methacrylate-grafted natural rubber latex and then carrying out prevulcanization, we obtained blends with stable viscosities. Under certain blending ratios, the blends maintained good basic properties, and the heat stability time (T,,,) of the blend increased with the increment of percent content of MG49 latex (C). The relationship between T,,, and C was T-HS = 0.36C + 33.0, whereas, the mechanical stability time (T-MS) was slightly decreased, and the relationship between T-MS and C was T-MS = -1.33C + 772.0; The modulus, antiaging properties, and tear strength of the films of the blends increased with the increment of C; the tensile strengths fluctuated on a small scope; the Shore A hardness (H) and breaking set (B,) both increased with the increment or C; their relationships were H = 0.66C + 40.0 and B-S = 0.46C + 8.0, respectively.