Solved by acgtyrant in post #2 
              
              
                OK, I check the source code torch.nn.init, just use the torch.no_grad: 
import torch
a = torch.nn.ConvTranspose2d(1, 1, 1)
with torch.no_grad():
    a.weight[0, 0, 0, 0] = 1
a.weight.requires_grad = False