SOURCE

new Vue({
    el: '#app',
    data() {
        return {
            list: [{
                test: [{
                    value: 1
                }]
            }, {
                test: [{
                    value: 1
                }]
            }]
        }
    },
    methods: {
        changeValue() {
            this.list[0].test[0].value += 1 
        },
        changeObject() {
            this.list[0].test[0] = {value: 5}
        }
    }

})

<div id="app">
    <p v-for="(item, k) in list" :key='k'>
        {{item.test[0].value}}
    </p>

    <button @click="changeValue">改变值</button>
    <button @click="changeObject">改变值</button>
</div>