A method of driving a transparent liquid crystal display apparatus includes a transparent display panel including a brightness sensor and a timing controller. The timing controller includes a YCbCr converter configured to convert input pixel data to YCbCr data, a histogram extractor configured to receive the YCbCr data and generate histogram information about the number of values corresponding to each of brightness data, a grayscale analysis unit configured to analyze the histogram information and determine a type of an input image, an image processer configured to process the YCbCr data according to the type of the input image and the ambient brightness information and generate an output YCbCr′ data, and an RGB converter configured to convert the output YCbCr′ data to output image data.