Objective To explore the effect of positive and expressive writing in elderly patients who are not informed about cancer diagnosis. Methods Totally 110 elderly cancer patients who were not informed about his/her cancer diagnosis were divided into a control group (n=56) and an observation group (n=54). Both groups received routine nursing, while the observation group was additionally provided with positive and expressive writing. The anxiety, depression, and quality of life were compared between the two groups before and after the intervention. Results After the intervention, the scores of anxiety, depression and social function of the observation group were significantly lower than the control group, while the score of life quality was significantly higher than the control group (all P<0.05). Conclusion Positive and expressive writing can reduce negative emotions of elderly cancer patients, help them establish positive psychological defense and improve their quality of life.