Miniaturized　lasers　with　on-demand　color　emission　have　immense　potential　in　the　development　of　integrated　imaging　sources.　Random　lasers　(RLs)　with　cavity-free　structures　and　low　spatial　coherence　are　promising　candidates　for　multicolor　imaging　sources.　However,　the　wide　tuning　range　and　high　tuning　accuracy　of　continuous　and　reversible　random　lasing　color　with　a　defined　emissive　direction　remain　challenging.　Here,　random　lasing　with　on-demand　color　emission　and　defined　emissive　direction　is　realized　in　fiber-integrated　microbelts　through　programmable　pumping.　Individual　RL　microbelts　as　RL　units　doped　with　blue　(B)-,　green　(G)-,　and　red　(R)-emissive　dyes　and　titanium　dioxide　nanoparticles　are　assembled　on　an　optical　fiber,　resulting　in　high-performance　B/G/R　lasing.　The　optical　fiber　functions　as　a　waveguide　that　guides　the　multicolor　RL　to　ensure　a　defined　directional　emission.　By　manipulating　the　combination　of　the　B/G/R　RL　units　on　the　waveguide,　distinctive　lasing　colors　covering　the　entire　visible　spectrum　are　obtained,　including　white-colored　random　lasing.　To　realize　dynamically　controllable　lasing　for　on-demand　color　emission,　a　pumping　strategy　with　programmable　excitation　is　proposed　by　shaping　the　pump　beams　into　different　beam　arrays　for　precisely　pumping　the　RL　unit　combination.　We　envision　that　fiber-integrated　RL　sources　can　be　implemented　in　various　imaging　applications,　such　as　biomedical　diagnosis,　multiplexed　communication,　and　optical　sensing.