Using a semiconductor saturable absorber mirror (SESAM) and a fiber loop mirror (FLM) as end mirror respectively, an all-fiber line-cavity Yb3+-doped laser is demonstrated. Q-switched pulse, Q-switched mode-locking, coherent mode-locking, harmonic pulses, and multiwavelength operation are obtained by adjusting the pump power and the polarization controller (PC). Mode-locking can be self-started and the width of mode-locking pulses is 31 ps. The pulse repetition rate is 19.3 MHz, corresponding to 40 pJ pulse energy. The spectral bandwidth of the mode-locked operation is 2.3 nm, at the center wavelength of 1030.8 nm. While multiwavelength operation centered at about 1033 nm is achieved, the wavelength space and the number of wavelength can be changed by adjusting the pump power and the PC. At the maximum pump power of 420 mW, the average wavelength space can be as small as about 0.11 nm. Up to 35 wavelengths within the spectral range of 10 dB are obtained, with 34 wavelengths in the 3 dB scale.