The holography of particle field by off-axis filter is an effective method for reducing the background noises and improving the reconstructed image quality. The filter size and the reconstructed particle image are closely related, a suitable filter size is important for the particle recognition and measurement. The relationship between the high-pass filter size, front focal length of 4F system, particle size and the intensity distribution of holographic reconstructed images of circle particle by off-axis filter are analyzed respectively, and the influences of different high-pass filter sizes on the same size particle images are simulated numerically. In addition,the off-axis filtering holography experiment is carried out. The results show that, the particle image contrasts are increased effectively by the high-pass filter. The uniformity of the reconstructed image intensity distribution becomes better, and the boundary gradient increases with the smaller the filter size or the larger the front focal length of 4F system, while with the increasing of particle size, some black and white circles appear gradually in the reconstructed particle image interior, and the particle boundary becomes increasingly clear.