“九年(nian)(nian)一貫(guan)制”學(xue)校(xiao)，通(tong)(tong)常是指該校(xiao)的(de)小學(xue)和初(chu)(chu)中施行一體化的(de)教(jiao)育(yu)，小學(xue)畢業(ye)后可直升(sheng)本(ben)校(xiao)初(chu)(chu)中，“小升(sheng)初(chu)(chu)”原則上不(bu)許擇校(xiao)流動，希望在本(ben)校(xiao)升(sheng)初(chu)(chu)中的(de)學(xue)生也不(bu)用為上初(chu)(chu)中費盡心思；九年(nian)(nian)一貫(guan)制學(xue)校(xiao)的(de)年(nian)(nian)級通(tong)(tong)常被稱為1年(nian)(nian)級、2年(nian)(nian)級……，至9年(nian)(nian)級。這樣在學(xue)生年(nian)(nian)齡較小，適(shi)應能力較弱的(de)時(shi)候的(de)教(jiao)育(yu)會有一個連(lian)貫(guan)性。

"十二(er)年一(yi)(yi)貫制學(xue)(xue)校(xiao)(xiao)(xiao)"是(shi)指集小(xiao)學(xue)(xue)、初中(zhong)(zhong)和高(gao)(gao)中(zhong)(zhong)為一(yi)(yi)體的12年一(yi)(yi)貫制學(xue)(xue)校(xiao)(xiao)(xiao)。學(xue)(xue)校(xiao)(xiao)(xiao)主要(yao)有三個特點，一(yi)(yi)是(shi)連貫性，學(xue)(xue)生可以(yi)從從一(yi)(yi)年級至(zhi)十二(er)年級，相繼完成小(xiao)學(xue)(xue)至(zhi)高(gao)(gao)中(zhong)(zhong)教(jiao)育，其間(jian)(jian)不(bu)(bu)間(jian)(jian)斷、不(bu)(bu)選拔(ba)。二(er)是(shi)就近入學(xue)(xue)、取消招生考(kao)試。小(xiao)升(sheng)初直接升(sheng)入本校(xiao)(xiao)(xiao)初中(zhong)(zhong)和高(gao)(gao)中(zhong)(zhong)，不(bu)(bu)必再受(shou)小(xiao)升(sheng)初、中(zhong)(zhong)考(kao)折磨(mo)之苦。三是(shi)實行統一(yi)(yi)的學(xue)(xue)校(xiao)(xiao)(xiao)行政、教(jiao)育、教(jiao)學(xue)(xue)管理(li)。

“完全中學”既(ji)有初(chu)級中學(xue)(xue)的學(xue)(xue)段(duan)，又有高級中學(xue)(xue)學(xue)(xue)段(duan)的學(xue)(xue)校，是一種學(xue)(xue)校制度(du)。

初(chu)中(zhong)(zhong)屬(shu)于(yu)9年義(yi)務教(jiao)育階段，而高中(zhong)(zhong)不屬(shu)于(yu)義(yi)務教(jiao)育，在學(xue)校的設置中(zhong)(zhong)，已經有許多完全中(zhong)(zhong)學(xue)脫鉤(gou)為兩所學(xue)校。

許多(duo)中(zhong)(zhong)(zhong)(zhong)學(xue)同時設(she)立(li)初(chu)中(zhong)(zhong)(zhong)(zhong)部及高中(zhong)(zhong)(zhong)(zhong)部，這些(xie)中(zhong)(zhong)(zhong)(zhong)學(xue)就(jiu)是(shi)完全中(zhong)(zhong)(zhong)(zhong)學(xue)。不過，國家(jia)規(gui)定(ding)國家(jia)級重(zhong)點(dian)中(zhong)(zhong)(zhong)(zhong)學(xue)和(he)省級重(zhong)點(dian)中(zhong)(zhong)(zhong)(zhong)學(xue)不許開設(she)初(chu)中(zhong)(zhong)(zhong)(zhong)，但是(shi)還(huan)是(shi)有一(yi)些(xie)學(xue)校(xiao)違規(gui)操作。有一(yi)些(xie)重(zhong)點(dian)中(zhong)(zhong)(zhong)(zhong)學(xue)通過開辦分校(xiao)等(deng)形式(shi)開設(she)初(chu)中(zhong)(zhong)(zhong)(zhong)，規(gui)避(bi)這一(yi)規(gui)定(ding)。由于歷史(shi)的原(yuan)因(yin)，一(yi)些(xie)曾(ceng)經開設(she)初(chu)中(zhong)(zhong)(zhong)(zhong)但后(hou)來取(qu)消了初(chu)中(zhong)(zhong)(zhong)(zhong)部或(huo)者不直接開設(she)的，仍然被稱為(wei)完全中(zhong)(zhong)(zhong)(zhong)學(xue)。