“九年(nian)(nian)一貫制”學(xue)(xue)校(xiao)，通常是指該(gai)校(xiao)的(de)小(xiao)(xiao)(xiao)學(xue)(xue)和初(chu)中(zhong)施行一體化的(de)教育(yu)，小(xiao)(xiao)(xiao)學(xue)(xue)畢業(ye)后可(ke)直(zhi)升本(ben)校(xiao)初(chu)中(zhong)，“小(xiao)(xiao)(xiao)升初(chu)”原則上(shang)不許擇校(xiao)流動，希望在本(ben)校(xiao)升初(chu)中(zhong)的(de)學(xue)(xue)生(sheng)也不用為上(shang)初(chu)中(zhong)費(fei)盡心思；九年(nian)(nian)一貫制學(xue)(xue)校(xiao)的(de)年(nian)(nian)級通常被稱(cheng)為1年(nian)(nian)級、2年(nian)(nian)級……，至9年(nian)(nian)級。這樣(yang)在學(xue)(xue)生(sheng)年(nian)(nian)齡(ling)較小(xiao)(xiao)(xiao)，適應能力較弱的(de)時(shi)候的(de)教育(yu)會有一個(ge)連貫性。

"十(shi)二年一(yi)(yi)(yi)貫(guan)制學(xue)(xue)(xue)校(xiao)"是指集小(xiao)學(xue)(xue)(xue)、初(chu)中(zhong)(zhong)(zhong)和高(gao)(gao)中(zhong)(zhong)(zhong)為一(yi)(yi)(yi)體的12年一(yi)(yi)(yi)貫(guan)制學(xue)(xue)(xue)校(xiao)。學(xue)(xue)(xue)校(xiao)主要有三個特點，一(yi)(yi)(yi)是連(lian)貫(guan)性，學(xue)(xue)(xue)生可(ke)以從從一(yi)(yi)(yi)年級至(zhi)十(shi)二年級，相繼完成小(xiao)學(xue)(xue)(xue)至(zhi)高(gao)(gao)中(zhong)(zhong)(zhong)教(jiao)育(yu)，其間(jian)不(bu)(bu)間(jian)斷、不(bu)(bu)選拔。二是就(jiu)近(jin)入學(xue)(xue)(xue)、取消招生考(kao)試。小(xiao)升初(chu)直接升入本校(xiao)初(chu)中(zhong)(zhong)(zhong)和高(gao)(gao)中(zhong)(zhong)(zhong)，不(bu)(bu)必再受小(xiao)升初(chu)、中(zhong)(zhong)(zhong)考(kao)折磨之苦。三是實行(xing)統一(yi)(yi)(yi)的學(xue)(xue)(xue)校(xiao)行(xing)政、教(jiao)育(yu)、教(jiao)學(xue)(xue)(xue)管理。

“完(wan)全中學”既有初級中(zhong)學(xue)的(de)學(xue)段，又有高級中(zhong)學(xue)學(xue)段的(de)學(xue)校(xiao)，是一種學(xue)校(xiao)制度。

初中(zhong)屬于9年義務教(jiao)(jiao)育(yu)(yu)階(jie)段，而(er)高中(zhong)不屬于義務教(jiao)(jiao)育(yu)(yu)，在學(xue)(xue)(xue)校的設(she)置中(zhong)，已經有許多完全(quan)中(zhong)學(xue)(xue)(xue)脫鉤為兩所學(xue)(xue)(xue)校。

許多(duo)中(zhong)(zhong)(zhong)(zhong)(zhong)學(xue)同時設(she)立初(chu)中(zhong)(zhong)(zhong)(zhong)(zhong)部及高(gao)中(zhong)(zhong)(zhong)(zhong)(zhong)部，這(zhe)些(xie)中(zhong)(zhong)(zhong)(zhong)(zhong)學(xue)就是完全(quan)中(zhong)(zhong)(zhong)(zhong)(zhong)學(xue)。不過，國家規(gui)定國家級(ji)重(zhong)點(dian)(dian)中(zhong)(zhong)(zhong)(zhong)(zhong)學(xue)和(he)省級(ji)重(zhong)點(dian)(dian)中(zhong)(zhong)(zhong)(zhong)(zhong)學(xue)不許開(kai)設(she)初(chu)中(zhong)(zhong)(zhong)(zhong)(zhong)，但是還是有一(yi)些(xie)學(xue)校(xiao)違規(gui)操作。有一(yi)些(xie)重(zhong)點(dian)(dian)中(zhong)(zhong)(zhong)(zhong)(zhong)學(xue)通過開(kai)辦分校(xiao)等形式開(kai)設(she)初(chu)中(zhong)(zhong)(zhong)(zhong)(zhong)，規(gui)避這(zhe)一(yi)規(gui)定。由于歷史的原因(yin)，一(yi)些(xie)曾經開(kai)設(she)初(chu)中(zhong)(zhong)(zhong)(zhong)(zhong)但后來取(qu)消了初(chu)中(zhong)(zhong)(zhong)(zhong)(zhong)部或(huo)者不直接開(kai)設(she)的，仍然被(bei)稱為(wei)完全(quan)中(zhong)(zhong)(zhong)(zhong)(zhong)學(xue)。