¡@¡@Currently, The Cr-doped fibers are grown by LHPG method or drawing-tower technique. The Cr-doped YAG preform was firstly fabricated by a rod-in-tube method. We have successfully fabricated the Cr-doped fibers by using a commercial drawing-tower technique. By employing a negative pressure control in drawing-tower technique on the YAG preform, the Cr-doped fibers with a better core circularity and uniformity, and good interface between core and cladding were fabricated. The core non-circularity was smaller than 3%, the spontaneous emission spectrum showed the bandwidth that approach to 300 nm, and the output power density level have promoted to a few nW/nm. ¡@In this study, we focused on the analysis of dynamic fluorescent characteristics of Cr-doped fibers in order to improve the quality effectively. The lifetimes of Cr4+ fluorescence and concentration of Cr ions were 1.5 £gs and 510 £gg/g, respectively.The concentration of the Cr ions was less than the Cr-doped fibers grown by LHPG method. The high-resolution micrograph showed that there was nano-crystalline structure in the core surrounded by SiO2 amorphous matrix. These nano-particles gathered at the core and formed micrometer clusters, and therefore resulted in high scattering loss around 1.17dB/cm. ¡@¡@In order to improve the Cr-doped fibers quality, reduce propagation loss, and promote the spontaneous emission power density. We have to decrease the temperature and drawing speed in the drawing process Therefore, the new Cr-doped fibers may have the potential for being used as a new generation broadband fiber amplifier to cover the bandwidth of the entire 1.3-1.6 £gm range which exhibit 300 nm usable spectral bands.