A　threshold　effect　in　the　periodical　patterning　of　the　hybrid　halide　perovskites　and　a　directional　output　coupling　effect　in　the　incoherent　random　lasing　from　the　patterned　materials　are　reported.　Using　1D　gratings,　the　random　crystallization　process　is　confined　into　the　grating　grooves,　producing　continuous　microstrips　of　CH3NH3PbBr3　along　the　groove　channels.　However,　the　confinement　is　strongly　dependent　on　the　width　of　the　grating　grooves,　which　can　be　optimized　by　tuning　the　patterning　periods.　It　is　thus　discovered　that　the　most　orderly　arranged　crystal　strips　are　achieved　for　a　grating　period　of　10　mu　m,　corresponding　to　a　channel　width　of　about　5　mu　m,　which　is　the　lower　limit　for　the　formation　of　continuous　crystal　strips.　Complicated　interfaces　inside　such　randomly　organized　multicrystals　supplied　scattering　centers　for　optical　gain　mechanisms.　Thus,　incoherent　random　lasing　actions　are　observed　for　all　of　these　patterned　structures,　however,　the　best　lasing　performance　is　achieved　for　a　grating　period　of　10　mu　m,　which　agrees　with　the　highest　quality　of　the　crystal　strips.　The　patterned　substrate　with　a　1D　grating　supplies　mechanisms　for　directional　crystallization　of　hybrid　halide　perovskites　and　directional　output　coupling　of　random　laser　emission,　enhancing　significantly　the　practical　application　possibilities　of　such　random　lasers.