A phosphorus-containing polyester composite and method of manufacturing the same is related to the field of compound formulation. The composite is prepared by condensation under certain conditions of (A) a poly-functional phosphorus-containing aromatic hydroxy compound; (B) a difunctional aromatic acryl chloride compound and (C) a monofunctional aromatic phenol compound used as a blocking agent. The composite is used as a curing agent for epoxy. The phosphorus-containing polyester composite is reacted with the epoxy group of the epoxy to obtain non-halogen and flame-retardant cured composite being environment friendly and having low dielectric, low dielectric loss factor and high heat resistance. It can be used in an integrated circuit board and used as a semiconductor packaging material.

A phosphorous-containing compound is represented by Formula (I): ##STR00001## wherein n is an integer ranging from 1 to 4; R.sup.1 represents hydrogen or a linear or branched C.sub.1-C.sub.4 alkyl group, and a plurality of R.sup.1s are the same or different when n is larger than 1; R.sup.2 represents hydrogen, ##STR00002##
or ##STR00003##
wherein Ep is an epoxy resin moiety; or ##STR00004##
represents ##STR00005##
wherein Ar represents a linear or branched C.sub.1-C.sub.12 alkyl group or a C.sub.6-C.sub.12 aryl group; and R.sup.3 represents hydrogen or methyl.

A phosphorous-containing compound is represented by Formula (I):

##STR00001## wherein n is an integer ranging from 1 to 4; R.sup.1 represents hydrogen or a linear or branched C.sub.1-C.sub.4 alkyl group, and a plurality of R.sup.1s are the same or different when n is larger than 1; R.sup.2 represents hydrogen,

##STR00002##

wherein Ep is an epoxy resin moiety; or

##STR00003##

represents

##STR00004##

wherein Ar represents a linear or branched C.sub.1-C.sub.12 alkyl group or a C.sub.6-C.sub.12 aryl group; and R.sup.3 represents hydrogen or methyl.

The purpose of the present invention is to provide: an epoxy resin composition which enables the achievement of a resin cured product that has high flame retardancy and excellent mechanical characteristics; and a prepreg and a fiber-reinforced composite material, each of which uses this epoxy resin composition. One embodiment of the epoxy resin composition according to the present invention, said epoxy resin composition having achieved the above-described purpose, contains the components (A) and (B) described below. (A): a bifunctional glycidyl amine type epoxy compound (B): an epoxy compound having a specific structure and/or an epoxy compound having another specific structure.