Both 需要 and 须要 mean need, require, want, demand. Their share the same pronunciation and very similar meanings, but their usages are different.
需要 (xūyào)
需要 can be a verb or a noun. It can have a noun, verb, or clause as its object and can be used as an attribute.
As a verb
e.g.
我的孩子们需要我，我必须马上回家。(Wǒ de háizi men xūyào wǒ, wǒ bìxū mǎshàng huí jiā.) My children need me; I must go home immediately.
如果需要帮助，请告诉我。(Rúguǒ xūyào bāngzhù, qǐng gàosù wǒ.) If you need help, please tell me.
我的成功需要大家的支持。(Wǒ de chénggōng xūyào dàjiā de zhīchí.) My success requires everyone’s support.
他现在最需要的是钱。(Tā xiànzài zuì xūyào de shì qián.) What he needs most right now is money.
As a noun
e.g.
我会尽量满足你们的需要。(Wǒ huì jǐnliàng mǎnzú nǐmen de xūyào.) I will try my best to meet your needs.
由于工作的需要，我们要出国了。(Yóuyú gōngzuò de xūyào, wǒmen yào chūguó le.)Due to work requirements, we need to go abroad.
你要从实际需要出发来想问题。(Nǐ yào cóng shíjì xūyào chūfā lái xiǎng wèntí.) You should think about the issue from the perspective of practical needs.
这个计划是领导的需要还是人民的需要？(Zhège jìhuà shì lǐngdǎo de xūyào háishì rénmín de xūyào?) Is this plan a requirement of the leaders or a need of the people?
须要 (xūyào)
须要 is an auxiliary verb and can only be used before verbs or adjectives.
e.g.
做工作就须要认真。(Zuò gōngzuò jiù xūyào rènzhēn.) When working, you must be serious.
这个问题须要认真思考。这个问题须要认真思考。(Zhège wèntí xūyào rènzhēn sīkǎo.) This issue requires serious consideration.
你须要好好休息。(Nǐ xūyào hǎohǎo xiūxi.) You need to rest well.
你须要有思想准备，你的银行快倒闭了。你须要有思想准备，你的银行快倒闭了。(Nǐ xūyào yǒu sīxiǎng zhǔnbèi, nǐ de yínháng kuài dǎobì le.) You need to be mentally prepared; your bank is about to go bankrupt.
Summary
“需要” as a versatile word that can function as a verb or noun, and “须要” as an auxiliary verb used before verbs or adjectives.
Exercise
