Abstract: From April 2001 to June 2003,the flocking behavior of Reevess pheasants (Syrmaticus reevesii) was studied in the Dongzhai National Nature Reserve,Henan Province,and Foping County,Shaanxi Province.We tracked 17 pheasants captured and radio-collared,moreover,recorded 328 times of pheasants activities in the field.The result shows that the male and female have different tendency in flocking (χ2=18.177,df=3,P=0.000).The adult male occupies stable home range all over the year.It usually moves solely or with a specifically male fellow and with some fixed females who wander in its home range.The females usually build up a flock including 4-6 individuals.The flock moves about in different males home ranges in non-breeding season and the beginning of breeding season.The flock separates while the female begin to incubate.In the late 10 days of June,the failing female in breeding begins to rebuild the flock and wander again.In winter,especially after snow,different flocks can build up a bigger flock for a short time,which includes many males and females.The sexual difference of flock in the species may be related to the differences of predation pressure and mating competition (male>female).