Ultrashort　laser　pulses,　featuring　remarkable　spectral　tunability,　are　highly　demanded　for　nonlinear　light-matter　interactions　in　a　variety　of　molecules.　Here,　we　report　on　the　generation　of　soliton-plasma-driven　ultrashort　pulses　with　both　bandwidth-and　wavelength-tunability　in　the　visible　spectral　region.　Using　He-filled　single-ring　photonic　crystal　fiber　(SR-PCF),　we　demonstrate　in　the　experiments　that　the　spectral　bandwidths　of　blueshifting　solitons　can　be　manipulated　by　adjusting　the　input　pulse　energy,　gas　pressure　and　core　diameter　of　the　SR-PCF,　while　the　central　wavelengths　of　these　solitons　can　be　continuously　tuned　over　200　nm.　We　found　that　in　a　large-core　SR-PCF　(24.6-mu　m　core　diameter),　the　bandwidths　of　blueshifting　solitons　can　be　effectively　broaden　to　near　100　nm,　pointing　out　the　possibility　of　generating　few-cycle,　wavelength-tunable　visible　pulses　using　this　set-up.　In　addition,　we　observed　in　the　experiments　that　in　a　small-core　SR-PCF　(with　a　core　diameter　of　17　mu　m),　the　blueshifting　solitons　show　little　residual　light　near　the　pump　wavelength,　resulting　in　a　high-efficiency　frequency　up-conversion　process.　These　experimental　results,　confirmed　by　numerical　simulations,　pave　the　way　to　a　new　generation　of　compact,　ultrashort　light　sources　with　excellent　tunability　at　visible　wavelengths,　which　may　have　many　applications　in　the　fields　of　time-resolved　spectroscopy　and　ultrafast　nonlinear　optics.　(C)　2019　Optical　Society　of　America　under　the　terms　of　the　OSA　Open　Access　Publishing　Agreement.