Here,　a　facile　self-templating　approach　is　presented　for　synthesis　of　hollow　and　yolk-shell　mesoporous　silica　nanoparticles　(HMSNs　and　YMSNs)　through　a　selective　etching　of　hybrid　silica　nanoparticles.　The　hybrid　silica　nanoparticles　are　from　the　co-condensation　of　tetraethylorthosilicate　(TEOS)　and　N-[3-(trimethoxysilyl)propyl]ethylenediamine　(TSD)　by　a　simple　one-step　process.　Two　kinds　of　products　including　HMSNs　and　YMSNs　can　be　easily　prepared　only　by　tuning　the　TSD　amounts　in　the　precursor.　Significantly,　the　transformation　of　hollow　structure　does　not　use　any　sacrificial　template　and　surface-protective　agent.　The　etching　mechanism　and　formation　process　are　systematically　investigated　by　SEM,　TEM,　TG,　CHN　elemental　analysis　and　Si　MAS　NMR　spectroscopy.　The　results　reveal　that　the　selective　etching　is　mainly　attributed　to　the　discrepancy　in　density　between　the　outer　layer　and　inner　area　of　hybrid　silica,　where　its　inner　section　is　more　readily　dissolved　while　the　outer　shell　is　robust　in　hydrofluoric　acid　(HF)　aqueous　solution.　Specifically,　the　new　understanding　is　further　extended　to　precisely　prepare　multi-shelled　hollow/yolk-shell　silica　nano-particles.