Single-crystalline FeTe 2 in marcasite phase with orthorhombic structure was prepared via chemical vapor transport. Cooling FeTe 2 single crystals from room temperature down to 2 K, multiple magnetic phase transitions were observed. Paramagnetic (PM) to antiferromagnetic (AFM) and then to ferromagnetic (FM) occurred at 79 K and 35 K for in-plane, 73 K and 29 K for out-of-plane, respectively. A strong uniaxial magnetic anisotropy was found due to FeTe 6 octahedron distortion and structural modulation in FM region. The novel negative volume expansion (NVE) initiated in the vicinity of AFM to FM transition. An abrupt frequency shift of the most intense mode at 118 cm −1 and evolution of the Te-Te stretching mode near 40 K, corresponding to the phase transition from AFM to FM were observed. The temperature-dependent resistance revealed an anomaly (semiconductor to metallic transition) around AFM-FM transition, which can easily be suppressed and move to high temperature by the applied magnetic field. The results from XRD, Raman and resistivity indicated that the structural parameters, vibration frequency and transport are sensitive to the phase transition from AFM to FM. The nature of direct band gap with 0.67 eV was identified through UV-Vis-NIR spectrum of FeTe 2 single crystals at room temperature.