When　the　concept　of　＇Narrow　Road,　Intensive　Grid,　and　Open　Space＇　commenced　to　be　popularized　in　Chinese　urban　planning,　some　citizens　had　serious　doubts　about　whether　permeable　environment　could　cause　crime　and　unsafety　or　not.　Theoretically,　which　one　was　safer,　open　or　enclosed　space?　Which　one　was　more　critical　on　safety,　design　or　management?　What　were　the　differences　between　factors　influencing　crime　behavior　and　safety　perception?　All　these　academic　debates　were　not　resolved　in　criminal　geography.　This　paper　discussed　how　built　environment　around　communities　influenced　crime　behavior　and　sense　of　security　on　the　basis　of　social　investigations,　criminal　cases　and　geographic　data　in　Beijing.　Among　them,　the　subjective　evaluation　and　objective　indicators　were　introduced　to　measure　features　of　physical　environment.　On　the　other　hand,　crime　occurrence　was　illustrated　by　both　the　criminal　recalls　and　crime　cases　on　record.　This　research　indicated　that　the　theory　of　which　was　better　open　or　enclosed　space　actually　depended　on　its　space　dimension.　An　enclosed　community　could　make　the　residents　feel　safer　and　restrain　low-dimensional　crime　activities,　yet　it　caused　the　＇crowding-out＇　effect　of　crime　activities.　Therefore,　＇Door　closing＇　was　unable　to　decrease　crime　rate　essentially.　Secondly,　the　influencing　mechanism　of　crime　behavior　was　quiet　different　from　safety　perception.　Open　space　with　intensive　social　activities,　mixed　urban　function　and　high　permeability　had　positive　effects　on　sense　of　security.　However,　it　allowed　criminals　to　have　more　targets　and　increase　their　survival　possibility　which　contributed　to　the　occurrence　of　crimes.　Thirdly,　compared　with　the　＇hard＇　section　of　physical　environment,　the　＇soft＇　section　of　management　and　maintenance　played　a　more　important　role　in　improving　safety　perception.　Meanwhile,　it　could　decrease　the　number　of　criminal　activities　in　a　higher　spatial　dimension.　In　summary,　planners　and　governors　should　pay　more　attention　to　environmental　maintenance　and　management　as　well　as　urban　design　in　order　to　pursue　crime　prevention.　©　2019,　Science　Press.　All　right　reserved.