Pepper(Capsicum spp.) derives from American tropics, and includes five varietiesCapsicum annuum, C.chinense, C.frutescens, C.baccatum, C.pubecens and some wild species, its genetic evolvable background, interspecific crossing barriers (unilateral incompatibility, seed abortion and cytoplasmic male sterility), control of chromosomal ploidy, and molecular breeding (construction of molecular linkage genetic map, molecular tagging of qualitative and quantitative traits were summarized in this paper.