What is the difference between 过于，过度 and 过分

Hi,“过于”it means "excessively",is used before adjectives or verbs expressing mental states,expressing that the degree and quantity have exceeded the limit. 例如：过于伤心;过于乐观。”过度“ it means "excess,go to far",it represents more than a specified amount,with a hint of dissuasion in it. 例如：悲伤过度;谦虚过度;过度的睡眠可能是身心失调的征兆。”过分“it means "excess", it refers a kind of behaviour that is too radical, beyond the duty and a certain limit, which makes people feel disgusted or even irritated. 例如：二哥的话未免太过分了 ;火山，过分的热情，反而成了一种灾害。

过于, 过度, and 过分 are all adverbs that express the idea of excessive or going beyond a certain limit. However, they are used in different contexts and have slightly different connotations.

过于 (guòyú) is used to indicate that something is excessively or excessively high or low in degree, amount, or intensity. It is often used to express subjective feelings, opinions, or judgments about a situation. For example:
这个菜的辣味过于强烈了。(Zhège cài de làwèi guòyú qiángliè le.) - The spiciness of this dish is excessively strong. 她的自信心过于低了。(Tā de zìxìn xīn guòyú dī le.) - Her self-confidence is excessively low.

过度 (guòdù) is used to indicate that something is excessive or goes beyond a reasonable or appropriate limit. It is often used to describe actions, behaviors, or processes that have negative consequences. For example:
他的工作狂热导致过度疲劳。(Tā de gōngzuò kuángrè dǎozhì guòdù píláo.) - His workaholic attitude has led to excessive fatigue. 过度使用这种化学药品会危害环境。(Guòdù shǐyòng zhè zhǒng huàxué yàopǐn huì wéihài huánjìng.) - Overusing this chemical can harm the environment.

过分 (guòfèn) is used to indicate that something is excessive or extreme, often in a negative or unfair way. It is often used to describe emotions, attitudes, or actions that are considered inappropriate or unreasonable. For example: 他的想法过分偏激。(Tā de xiǎngfǎ guòfèn piānjī.) - His ideas are extremely biased. 老板对员工的要求过分苛刻。(Lǎobǎn duì yuángōng de yāoqiú guòfèn kēkè.) - The boss's demands on employees are excessively harsh.

In short, 过于 is used to indicate subjective judgment or feeling about excessive degree, 过度 is used to describe excessive or over-the-limit actions or behaviors, and 过分 is used to describe excessive or extreme emotions or attitudes. I hope this helps.