1. A system for patient risk level evaluation, implemented with a remote medical care center, wherein the remote medical care center connects with a plurality of health care locations over a network, comprising: an input interface, connecting to each of the plurality of health care locations, receiving patient data of a plurality of patients from the plurality of health care locations; a processor, comprising: an event determination unit, determining an occurred event for each patient according to the corresponding patient data; a classification unit, classifying each of the occurred events into a deteriorating category or an ameliorating category; a group sorting unit, sorting the patients corresponding to the same events into a group, and ranking the patients within the group according to severity of illness of each patient; a risk evaluation unit, determining a risk score for each patient based on the corresponding event according to the equation A=D+(ΣW i E i ), wherein A is the risk score of the corresponding patient, D is a mortality risk of the occurred event for the corresponding patient, W is a weight of the relative factors of the occurred event for the corresponding patient, and E is a score reflecting the abnormality level of the relative factors of the occurred event for the corresponding patient; and a category ranking unit, generating a patient ranking order for the deteriorating category corresponding to the risk score in the order from high to low, and generating a patient ranking order for the ameliorating category corresponding to the risk score in the order from low to high, respectively; and an output interface, displaying the patient ranking order for the deteriorating category, and displaying the patient ranking order for the ameliorating category.