Phase transformations of 100nm Ge1Sb4Te7 films induced by single 130fs pulse at 800nm have been investigated with time-resolved microscope. With an average fluence of 30mJ/cm2, a reflective intensity increase was observed within 1ps in 100nm as-deposited Ge1Sb4Te7 films after excitation by intense femtosecond pulse, which was consistent to an electronically induced non-thermal phase transformation. XRD measurement confirmed that single femtosecond pulse could induce crystalline marks in 100nm as-deposited Ge1Sb4Te7 films. Our results indicated that single femtosecond pulse could trigger both crystalline and amorphous phase in 100nm Ge1Sb4Te7 films. The fluence for crystallization was higher than that for amorphization.