在service配置文件中添加环境变量Environment 具体操作如下：   

1.创建保存模型目录文件夹

sudo mkdir /home/xyh/data/ollama/models
sudo chmod 777 /home/xyh/data/ollama/models

2.修改service配置并添加环境变量Environment 

sudo vi /etc/systemd/system/ollama.service 
#将变量参数添加到service配置文件并保存  
Environment="OLLAMA_MODELS=/home/xyh/data/ollama/models"  
Environment="OLLAMA_HOST=0.0.0.0:11434" 

修改后service配置文件内容如下：  

[Unit]  
Description=Ollama Service  
After=network-online.target
[Service]  
ExecStart=/usr/local/bin/ollama serve  
User=ollama  
Group=ollama  
Restart=always  
RestartSec=3  
Environment="PATH=/media/xyh/_dde_data/tools/jdk1.8.0_291/bin:/home/xyh/anaconda3/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/sbin:/usr/sbin:/usr/local/nodejs/bin"  
Environment="OLLAMA_MODELS=/home/xyh/data/ollama/models"  
Environment="OLLAMA_HOST=0.0.0.0:11434"  
[Install]  
WantedBy=default.target  

3.重新加载配置文件，并重启ollama服务使配置文件生效  

sudo systemctl daemon-reload  
sudo systemctl restart ollama