  In this study, we concentrate on the formation and evolution of hot subdwarfs
binaries through the stable Roche lobe overflow (RLOF) channel of
intermediate-mass binaries. We aim at setting out the properties of hot
subdwarfs and their progenitors, so that we can understand the formation and
evolution of hot subdwarfs comprehensively. We have obtained the ranges of the
initial parameters of progenitor binaries and the properties of hot subdwarfs
through the stable RLOF channel of intermediate-mass binaries, e.g. mass,
envelope mass and age of hot subdwarfs. We have found that hot subdwarfs could
be formed through the stable Roche lobe overflow at main sequence and
Hertzsprung gap. We have also found that some subdwarf B or OB stars have
anomalous high mass (around 1 solar mass) with thick envelope (0.07 solar mass
to 0.16 solar mass) in our models. By comparing our theoretical results with
observations on the hot subdwarfs in open clusters, we suppose a quantity of
hot subdwarfs in binary systems might be found in open clusters in the future.
