Photovoltaic devices based on dye-sensitized solar cells (DSSCs) have attracted great attention owing to their prospect of high energy conversion efficiency and low production cost. The power conversion efficiency and the long term stability have been reported to be improved by incorporating carbon nanotubes (CNTs) into the front electrode. However, methods to fabricate electrodes made of carbon nanotube composites are often high in cost, e.g. chemical vapour deposition (CVD), or involve some complicated procedures, e.g. functionalization of CNTs with titanium dioxide (TiO2). Here we report morphological and optical characterizations of DSSC composite electrodes composed of multi-walled carbon nanotubes (MWCNTs) and TiO2. The composite electrodes were fabricated by a direct mixing method with aid of organic surfactants. The electrodes containing MWCNTs of 0.025! by weight enhanced the power conversion efficiency by a factor of 1.42, under the Air Mass 1.5 illumination standard for an active area of 0.36 cm2. The morphology and the composition of the films were characterized by the Field-Emission Scanning Electron Microscope (FE-SEM) as well as the Raman Spectroscopy and Microscopy. The optical transparency of the composite films was revealed by the optical absorption spectroscopy. The SEM results indicate that the increase in the electrode active surface area induced by the MWCNTs is not sufficient to account for the DSSC efficiency improvement, of which the mechanism should be best explained by the improved conductivity of the films from the MWCNTs additives. On the contrary, with MWCNTs additives of over 1!, the conversion efficiency decreases gradually, which seems to result from a poor optical transparency of the composite films.